Error 10548 when trying to connect API in Modern Events Calendar

[robertallan]

We are using the Modern Events Calendar plugin to process event payments and are getting the following error when enabling the PayPal Credit Card payment option. 

(10548) This transaction cannot be processed. The merchant's account is not able to process transactions.

From my research, it looks like we may need to enable "PayPal Payments Pro" on this account, but I'm not able to find where / how to do this. We are using a business account and have set up API credentials as requested. 

Please advise. Thank you!

[robertallan]

Anyone out there that can help with this? Seems like it should be pretty simple, but am not able to find how to enable. Thank you!